4.72 a full-wave bridge-rectifier circuit with a 1-k load operates from a 120-v (rms) 60-hz household supply through a 12-to-1 step-down transformer having a single secondary winding. it uses four diodes, each of which can be modeled to have a 0.7-v drop for any current. what is the peak value of the rectified voltage across the load? for what fraction of a cycle does each diode conduct? what is the average voltage across the load? what is the average current through the load? d 4.73 i